Apparatus for roll counter-deflection in rolling stands

ABSTRACT

A ROLLING STAND, ESPECIALLY A TWO-HIGH OR A FOUR-HIGH ROLLING STAND, HAS A DOWNWARD ROLLING PRESSURE ONTO A ROLL, WHICH PRESSURE IS ABSORBED BY THE STOCK WHEN PRESENT AND BY THE ROLL BEARINGS. THE PRESENT INVENTION IS TO AVOID EXCESS LOAD ON THE BEARINGS AND THEIR MOUNTINGS FOR A GIVEN ROLLING PRESSURE BY COUNTER-DEFLECTING THE ROLL. A CROSS BEAM OF THE ROLL STAND IS PARALLEL AND ABOVE THE ROLL AND BACK-UP ROLLS ARE PROVIDED TO SPACE THE CROSS BEAM FROM THE ROLL, DEFLECTING DEVICES ARE PROVIDED TO CONNECT THE CORRESPONDING ENDS OF THE ROLL AND CROSS BEAM, SO THAT OPERATION OF THE DEFLECTING DEVICES URGES TOGETHER SAID CORRESPONDING ENDS.

Dec. 14, 1971 wlLLEKE ETI'AL 3,626,739

APPARATUS FOR ROLL COUNTER-DEFLECTION IN ROLLING STANDS Filed July 8, 1969 54 7 29 2e 55 2 r w: m w" A l 52 23 24 55 Fig. 3

INVENTOR.

HORST WILLEKE ET AL 8%) {WM I United States Patent US. Cl. 72241 3 Claims ABSTRACT OF THE DISCLOSURE A rolling stand, especially a two-high or a four-high rolling stand, has a downward rolling pressure onto a roll, which pressure is absorbed by the stock when present and by the roll bearings. The present invention is to avoid excess load on the bearings and their mountings for a given rolling pressure by counter-deflecting the roll. A cross beam of the roll stand is parallel and above the roll and back-up rolls are provided to space the cross beam from the roll; deflecting devices are provided to connect the corresponding ends of the roll and cross beam, so that operation of the deflecting devices urges together said corresponding ends.

This invention relates to an apparatus for the counterdeflection of rolls in roll stands arranged for the production of flat products. With an apparatus of this kind, the cross-sectional shape of fiat-rolled products can be influenced and the thickness tolerance narrowed, or an optimum product cross-section obtained.

In a two-high rolling mill, to prevent roll deflection, back-up rolls can be arranged between the spacer bridge joining the chocks or roll mounting members and the working roll, the said back-up rolls being pressed against the roll bodies by the action of power-operated devices.

A drawback of this arrangement is that the force, introduced to ensure that the back-up rolls form a system with the roll bodies that is free from play, has to be absorbed by the roll bearings or by the chocks surrounding them. When there is no stock to be rolled between the rolls, this force must be small, as it has to be absorbed solely by the small cross-section of the side of the chocks facing the roll gap. Any pre-bending of the rolls in the plane of the rolling force, i.e. the application of an advance load opposed to the action of the rolling force, is therefore impossible.

In addition, the bearing running clearance, essential for smooth functioning of the rolling mill, is produced on the side of the roll bearings away from the roll gap, so that at the start of the initial pass of the product to be rolled impacts occur on these bearing sides, which should absorb a part of the rolling pressure during rolling. Not until the product to be rolled is between the rolls, i.e. when a rolling force is present, could the contact pressure of the back-up rolls be intensified. Before the product leaves the rolls, the contact pressure would then have to be reduced again. However, this means that part of the length of the rolled product at the beginning and end is rolled with larger tolerances than the central part in between.

In another arrangement, the back-up rolls in four-high stands are provided on both sides with extended end portions or trunnions on which bearings are applied. Between the bearings on the roll trunnions of the top and bottom back-up rolls, hydraulic cylinders are fitted. When the cylinders are loaded, the roll trunnions are pushed apart, and the main bearings of the back-up rolls are dis- 3,626,739 Patented Dec. 14, 1971 advantageously loaded, in addition to the rolling force, with the reaction force to be exerted by them to produce deflection.

According to a first aspect of the invention, there is provided apparatus for deflecting a roll of a roll stand against the rolling pressure, the roll having extending end portions, the roll stand having a cross member with elements corresponding to each end portion of the roll, a back-up member or members between and adapted to space the cross member from the roll, and deflecting devices arranged to urge together each extending end portion and its corresponding element.

The roll stand can be a two-high or a four-high roll stand.

An apparatus according to the invention can provide counter-deflection of the back-up rolls independently of the rolling pressure without additional loading of the roll bearings absorbing the rolling pressure.

A closed deflection system free of play can be established between the cross-beam and the roll by the deflecting devices and the back-up rolls, so that the main bearings of the roll are not additionally loaded by the deflection force. Adjustment of the deflection force after an initial pass or after a screwdown can be no longer necessary. This can eliminate the danger, found in other devices, that the rolls will strike together as a result of the deflection force after the product has left the rolls. The force to be exerted by the power-operated devices according to the invention to produce a given deflection can be only about /3 of the force necessary for the two-high rolling mill described above, in which the deflection force is produced direct by a screwdown of the cambered roll. This can give a corresponding reduction in the surface pressure between the back-up roll and work roll and hence a reduction in the risk of markings.

Preferably the back-up members are back-up rolls arranged parallel to the roll, so that the surface pressure on the roll bodies can be further reduced.

The back-up rolls preferably run in bearings which are guided by means of lateral projections in a vertical guide in the mounting means of the roll.

This can avoid any twisting of the back-up rolls in relation to the rolls. The top roll and back-up rolls can be moved together, The device can be used in both twohigh and four-high stands.

The cross member may be a beam extending generally parallel to the roll.

The beam can have forked ends, through which screw means, for providing the rolling pressure, pass.

Preferably, the deflecting devices are pivotally mounted at the ends of the forked portions of the beam.

The parts comprising the deflecting devices and the extending end portions may be connected by a hook secured to one of said parts, the hook engaging in a yoke secured to the other of said parts.

Preferably, the extending end portions have bearings for connecting the end portions of the deflecting devices.

The power-operated devices can thus be adjusted to the respective position of the extending end portions and fork ends. Replacement of the top roll is also facilitated.

Preferably, the deflecting devices are hydraulically operated.

The roll can be a back-up roll for a working roll.

According to a second aspect of the invention there is provided a roll stand having the apparatus according to the first aspect of the invention.

The roll stand can have a top and a bottom roll, wherein only the top roll has the apparatus as claimed according to the first aspect of the invention,

Thus, the cost of a roll stand can be kept low.

The invention will be further described by way of example with reference to the accompanying drawings, of which:

FIG. 1 is a four-high rolling stand with a deflection device for the top back-up rolls;

FIG. 2 is a vertical cross-section through the roll chocks to the cross-beam; and

FIG. 3 is a plan view with the stand top removed, showing a cross-section through the central part of the cross-beam.

A roll stand consists of two housings 1 and 2 having openings in which chocks 3 and 4 of the top and bottom back-up rolls 5 and 6 are mounted. In the chocks 3 and 4, T-shaped apertures are provided, in each of which a T-shaped chock 7 and 8 for a work roll 9 or 10 is mounted. Between the horizontal surfaces of the chocks 3 and 7 or 4 and 8 respectively are cylinders 11 and 12 to produce a constant contact between the work rolls 9, 10 and the back-up rolls 5, 6 respectively.

To screw down the top back-up roll, 5 spindles 15, 16 each with a drive 13, 14 are mounted in the crosstie of the housing 1 and 2 and applied to the chocks through bolsters 17, 18. The chocks 4 of the bottom back-up roll 6 are each supported against a lower housing cross-tie 21, 22 through a pressure plate 19 and a pressure cup 20.

Two back-up rolls 25, 26 commonly supported in bearing housings 23, 24 are in contact with the bodies of the top back-up roll 5. The bearing housings 23, 24 are supported through pressure plates 27 and their respective pressure cups 28 against a deflection crossbeam 29, the forked ends of which pass by the spindles 15, 16.

In the region of the chocks 3, 4, the deflection crossbeam is provided on its underside with hook portions 30 which engage in the chocks 3, 4 provided on the upper side with suitable projections 31. In the projections are provided cylinders 32, the pistons of which are directed towards the hooks 30. When the cylinders 11, 12 and 32 are loaded, the system consisting of the deflection cross-beam 29, back-up rolls 25, 26, back-up roll 5 and work roll 9 with their bearings 23, 24, 3, 4 and 7, 8 are clamped into one unit free from play.

In its central region, the deflection cross-beam 29 is carried by four tie-rods 34, passing through an upper spacer bridge 33 of the rolling stand, each pair of the said rolls being connected by a cross-piece 35. On the spacer bridge 33 are mounted two cylinders 36 whose piston rods 37 are directed from below towards the cross-piece 35. In this way it is possible to balance the roll installation with back-up rolls 25, 26 and deflection cross-beam 29.

To obtain a counter-deflection of the back-up roll 5, a deflection cylinder 38, 39 is mounted on each forked end of the deflection cross-beam 29 on journals 40, 41, the piston rod being connected with a hook 42, 43. The top back-up roll is provided with extended necks onto which are pushed deflection bearings 46, 47 provided with two lateral journals 44, 45. On the journals 44, of each bearing there are butt straps 48, 49 connected by a bolt 50 or 51, which is engaged by the hook 42 or 43. When the cylinders 38, 39 are loaded, the deflection cross-beam 29 and back-up roll 5 are pulled together at their ends. As the distance between them at the centre is kept constant by the back-up rolls 25, 26 mounted between them, deflection on both sides of the deflection cross-beam 29 and back-up roll 5 around the back-up rolls 25, 26 takes place. This provides the possibility of counter-deflection of the back-up roll 5, in which the bearings of the back-roll are kept free from additional reaction forces.

To avoid twisting of the back-up rolls 25, 26 in relation to the back-up roll 5, side projections 52, 53 are provided on the bearing housings 23, 24 of the back-up rolls 25, 26, the said projections engaging in vertical guides 54, 55 provided on the chocks.

We claim:

1. A rolling mill comprising a frame with lateral windows, a plurality of relatively large rolls journalled one above the other in respective chocks located in said windows, the upper roll having its ends projecting through said windows, means for exerting a downward force on the chocks of the upper of said rolls, a vertically movable cross-beam disposed above and extending parallel to the upper roll, a relatively small ancillary roll urged against the mid-section of the upper roll by the cross-beam, and means for drawing together the corresponding ends of the cross-beam and the upper roll.

2. A rolling mill as claimed in claim 1 wherein a pair of relatively small ancillary rolls back up the upper roll and the ancillary rolls are journalled in bearings provided with projections engaging with vertical guides in opposed surfaces of the chocks of the upper roll.

3, A rolling mill as claimed in claim 1 wherein the means for drawing together the corresponding ends of the cross-beam and the upper roll comprises a fluid pressure operated piston and cylinder device mounted on each end of the cross-beam, a bearing sleeve fitting on each end of the upper roll and coupling means interconnecting each bearing sleeve with the piston of the piston and cylinder device mounted on the corresponding end of the cross-beam.

References Cited UNITED STATES PATENTS 3,171,305 3/1965 Stone 72-241 3,373,588 3/1968 Stone 72241 X 3,394,566 7/1968 OBrien 72-245 X 3,394,575 7/1968 Stone 72--245 THERON E. CONDON, Primary Examiner N. ABRAMS, Assistant Examiner US. Cl. X.R. 72-237, 245 

